<!-- 1、使用 border -->
<div class="border">border 实现</div>

<!-- 2、使用伪元素 -->
<div class="pesudo">伪元素实现</div>

<!-- 3、外 box-shadow -->
<div class="boxShadow">外 box-shadow 实现</div>

<!-- 4、内 box-shadow -->
<div class="insertBoxShadow">内 box-shadow 实现</div>

<!-- 5、drop-shadow -->
<div class="filterDropShadow">drop-shadow 实现</div>

<!-- 6、渐变 -->
<div class="linearGradient">线性渐变实现</div>

<!-- 7、outline -->
<div class="outline">outline 实现</div>

<!-- 8、滚动条 -->
<div class="scroll"></div>

<!-- 9、texr-decoration -->
<div class="textDecoration">texr-decoration</div>

<!-- 10、first-letter -->
<div class="fitstLetter">1</div>

<!-- 11、list-style -->
<div class="listStyle"></div>

<!-- <div class="listStyle2">11223344</div> -->

<style>
  @import url("https://fonts.googleapis.com/css2?family=Open+Sans:ital,wght@1,300&display=swap");

  html,
  body {
    width: 100%;
    height: 100%;
    display: flex;
    flex-wrap: wrap;
  }

  div {
    flex-shrink: 0;
    font-family: "Open Sans", sans-serif;
    position: relative;
    width: 200px;
    height: 60px;
    line-height: 60px;
    margin: 20px;
    background: #ddd;
    text-align: center;
  }

  .border {
    border-left: 5px solid deeppink;
  }

  .pesudo::after {
    content: "";
    width: 5px;
    height: 60px;
    position: absolute;
    top: 0;
    left: 0;
    background: deeppink;
  }

  .boxShadow {
    margin-left: 25px;
    box-shadow: -5px 0px 0 0 deeppink;
  }

  .insertBoxShadow {
    box-shadow: inset 5px 0px 0 0 deeppink;
  }

  .filterDropShadow {
    margin-left: 25px;
    -webkit-filter: drop-shadow(-5px 0 0 deeppink);
  }

  .linearGradient {
    background-image: linear-gradient(90deg,
        deeppink 0px,
        deeppink 5px,
        transparent 5px);
  }

  .outline {
    margin-left: 25px;
    height: 50px;
    outline: 5px solid deeppink;
  }

  .outline:after {
    position: absolute;
    content: "outline实现";
    top: -5px;
    bottom: -5px;
    right: -5px;
    left: 0;
    background: #ddd;
  }

  .scroll {
    position: relative;
    width: 205px;
    background: deeppink;
    overflow-y: scroll;
  }

  .scroll::-webkit-scrollbar {
    width: 200px;
    background-color: #ddd;
  }


  .textDecoration {
    overflow: hidden;


  }

  .textDecoration ::before {
    position: absolute;
    content: "_______";
    font-size: 40px;
    bottom: 30px;
    left: -15px;
    text-decoration: underline;
    color: deeppink;
    line-height: 60px;
    transform: rotate(90deg);
    right: 142px;
  }

  .fitstLetter {
    position: relative;
    overflow: hidden;





  }

  .fitstLetter::first-letter {
    background: deeppink;
    color: transparent;
    width: 5px;
    position: absolute;
    left: 0;
    top: 0;
    padding: 34px 0px;
    margin-left: -196px;
  }

  .fitstLetter::before {
    content: "::first-letter 实现";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
  }

  .listStyle {
    position: relative;
    display: list-item;
    list-style: square inside;
    padding-left: 5px;
    line-height: 0;
    font-size: 600px;
    overflow: hidden;
    background: deeppink;
    color: #ddd;


  }

  .listStyle::before {
    content: "list-style 实现";
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    color: #000;
    font-size: 16px;
    line-height: 60px;
    z-index: 1;
  }

  .listStyle2 {
    position: relative;
    display: list-item;
    list-style-type: square;
    list-style-position: inside;
    padding-left: 5px;
    line-height: 60px;
    font-size: 20px;
    overflow: hidden;
    background: deeppink;
    color: #ddd;
    animation: scale 5s infinite linear;
  }

  @keyframes scale {

    0%,
    30% {
      font-size: 20px;
    }

    80%,
    100% {
      font-size: 600px;
    }
  }
</style>